Class McpJson

java.lang.Object

dev.langchain4j.mcp.client.transport.McpJson

public final class McpJson
extends Object

Reads and writes MCP payloads through the pluggable JSON codec.

Method Summary

Modifier and Type	Method	Description
static <T> T	convert(Object value, Class<T> type)	Re-reads an already-decoded JSON value as the given type.
static <T> List<T>	convertList(Object value, Class<T> elementType)	Re-reads an already-decoded JSON array as a list of the given element type.
static <T> T	deserialize(String message, Class<T> type)	Deserializes an MCP message into a protocol type.
static <T,R> CompletableFuture<R>	map(CompletableFuture<T> source, Function<T,R> mapper)	Maps a future's value while keeping cancellation linked to the source.
static String	serialize(Object message)	Serializes an outbound MCP message.
static Map<String,Object>	toMap(String json)	Reads a JSON object as plain values.
static Object	toValue(String json)	Reads any JSON value as plain JDK types: a Map, a List, a boxed primitive, or null for a JSON null.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

deserialize

public static <T> T deserialize(String message,
 Class<T> type)

Deserializes an MCP message into a protocol type.

The message is taken as it arrived on the wire, so this is a single parse. Reading it into a tree first and then into a type costs two more passes and, for high-precision numbers, is not guaranteed to round-trip.

toValue

public static Object toValue(String json)

Reads any JSON value as plain JDK types: a Map, a List, a boxed primitive, or null for a JSON null.

Throws:

IllegalArgumentException - if the text is not valid JSON, or JsonException from a codec that reports the typed exceptions.

toMap

public static Map<String,Object> toMap(String json)

Reads a JSON object as plain values.

convert

public static <T> T convert(Object value,
 Class<T> type)

Re-reads an already-decoded JSON value as the given type.

convertList

public static <T> List<T> convertList(Object value,
 Class<T> elementType)

Re-reads an already-decoded JSON array as a list of the given element type.

serialize

public static String serialize(Object message)

Serializes an outbound MCP message. A null message renders as null rather than as the JSON null literal, so that an absent payload stays absent.

map

public static <T,R> CompletableFuture<R> map(CompletableFuture<T> source,
 Function<T,R> mapper)

Maps a future's value while keeping cancellation linked to the source. A plain thenApply would not propagate cancellation upstream, which would leave the transport's response stream open after the client cancels the operation.